Composite incandescent-lamp bulb and reflector.



No. 762,921 PATENTED JUNE 21, 1904.

0. A. MYGAT'I'.

COMPOSITE INGANDESCENT LAMP-BULB AND REFLECTOR. APPLICATION FILED JAN. 29. 1904.

no MODEL. I 2 SHEETS-SHEET 1.

PI G. 1. Y FIG. 2.

atloznu Y PATENTED JUNE 21, 1904.

0. A. MYGATT. COMPOSITE INGANDESGENT LAMP BULB AND REFLECTOR.

APPLICATION FILED JAN. 29. 1904.

2 BHEETS-SHEET 2.

aftoznelg NO MODEL.

2M Hum-ow GA. W

5 directed to the illumination of a definite predetermined area with maximum beneficial effeet; also, to provide a lamp-bulb and reflec- UNITED STATES orIs MYGATT, or NEW YORK, N. Y.

Patented June 21,

ENT

COMPOSITE l NCANDESCENT-LAMP BULB AND hEFLEoToR SPECIFICATION forming part of Letters Patent No.'7 62, 27, dated June 21 A plication filed January 29, 1904. Serial No. 191,138. (No model.)

To all whom, it may concern:

Be it known that I, OTIS A. MYeA'r'r, aciti-' zen of the United States, residing at New York,

in the county of New York and State of New York, have invented certain new and useful Improvements in Composite Incandescent- Lamp Bulbs and Reflectors, of which the fol-. V

lowing is'a specification.

This invention relates to combined electric- 1 lamp bulbs and reflectors composed wholly of glass.

The object of the invention is to produce a combined bulb and reflector each part, com-' posed of glass and forming when united a symmetrical whole of predetermined form;

also, to provide anai'r-space for the equalization of temperature of the surfaces where the reflector covers the bulb proper; also, to prov-ide a bulb which shall show no tip or protuberance in-, that part of the bulb outside the reflector, the exhaust or vacuum seal being or edge onlyand complete the symmetry of outline by covering a reduced part of the bulb; also, to provide a symmetrical form of bulb and reflector in which the light-rays reflected-fromusual forms of filament shall be tor which maybe shipped. as a single structure, the reflector acting as a guard or .pro tector for the bulb; also, to improve the'constructions and combinations above outlined, substantially as hereinafter indicated and claimed. I V

Figure 1 is a side elevation of a reflector and bulb formingtogether a generally spherical body when viewed externally. Fig. 2 is a verutical central section of the' same. Fig, 3 is a side elevation of a reflector and bulb forming together adouble conical body. Fig. 118a vertical central section of the same. Fig. 5 is a side elevation of a reflector and bulb in outward 'for m of'a peg-top. Fig. MS avertical central sectionof the same. -vation of a pear-shaped bulb and reflector, and Fig. 8 is avertical central section df Fig.-

of filament is generally employed. My con- Fig. 7, is an eleameter of said reflector being about-equal to It has heretofore been to connect areflector of glass for other material to an electric-lamp bulb near the top or socket of the bulb, therefle'ctor flaring out in conical or other form to partly cover the-bulb; but. usually the reflector has been of much greater diameter than the lamp-bulb. (See,for ex-- ample, my Patent No. 705,426; July 22, 1902.) In the patent of Goodchild, No. 634,295, of October 3, 1899,21 reflector is described which envelops the upper; end'of an electric-lamp bulb and fits as a petticoat or jacket thereon, L such reflector extending outwardly-onlya short distance from the lamp-bulb. Such a.-'.

reflector is supported throughout by the body of the lamp-bulb, which it neatly fits. In my Patent No. 732,211,- of J u'ne30,.19.03,-

a' flared prismatic glass, reflector is. shown resting on bulb.

That part of an incandescent electric lamp which is at the bottom when'the lamp is sus-]- by the greater quantity'of the light-rays projected downwardiy or away from the A and supportedby an electric-lamp 79 socket, such as by the making of'special fila- I ments, as well as by the provision of reflectors. In practice, however, it has been foundthat an approximately oval loop filament of one or more turns is most economical in construction. and of greatest enduranceyand such form struction of bulb and" reflector especially adapts itself to such filaments, although other formsof filament may be'usedrv In Figs. 1 andf2 th'ebulb proper is of The lower-portion .1 of this bulb is substantially a hemisphere-- 5 Above themedian portion or -zone 2 the bulb is of reduced diameter, the sides being preferably. f concave, as at'3, and brought'into the neck ig -where the metalliecap (covering the lamp-stem. 5) is at: tached in any usualmanner... ,lhe' filament 6 is inserted in the bulb in usual nanner. and is preferablythe common doubleoval loop.- A prismatic glass. reflector 7 of; the form of about a semisphere'is formed, thelgreatestdithat of the largest part of thelbulb. .This glass reflector has, external prismsi8 of'the i glass. 7

character frequently described by me as douhie-reflecting prismsthat is, such prisms asspace and prevents the excess of heat at this part. The bulb with the reflector applied presents the form of a sphere, with stem 5 at one end. The prisms 8 are in the form of lunes, extending from the stem to about the middle or largest diameter of the bulb.

The lower portion 1 of the bulb ispreferably ground or etched on its outer surface, as indicated by shading, Figs. 1 to 4. Incandescent-lamp bulbs are usually blown in a mold, and the air is afterward exhausted, generally from the end opposite the stem, and a tip is left on this end when the lamp is sealed.

Sometimes thebulb has been exhausted by other means, but such is more expensive than the tip exhaust. The tip is almost invariably at the-end opposite the stem, for the reason that although objectionable in any place it interferes less with the symmetry of the bulb at that point than at any other.

Instead of providing the tip and seal of the lamp at the end opposite the stem. I provide an exhaust-stem at some point, as 10, which is covered by the reflector 7. The exhausttube at this point may be of any usual. construction, and the sealing may be effected in any usual way; but as the seal is covered from observation by the reflector much less care need be expended in the finishing of the seal than would be the case were this part to be exposed to observation. As the seal is on that part of the lamp which is least luminous, the actual amount of light obstructed thereby is very small. The seal is fully protected by the reflector.

Figs. 3 and 4 illustrate a lamp-bulb which externally appears in form of two cones with their bases joined, the upper cone being truncated where the stem is attached to'the bulb. The lower part 11 of the bulb is of blown glass, as is the concave part 13, which is covered by the frusto-conical reflector 17. In this case, as in the preceding, the glass reflector is substantially covered externally'with integral prisms 18, which are double-reflecting prisms. The lower edge 19 of the reflector is beveled to form a continuation of the lower or inverted cone, and the inner face of the reflector bears on the outside of the bulb at the outer circumference instead of resting its edge on an enlargement of the bulb, as in Fig. 2.

own weight; but when inverted or when arranged to project light horizontally the reflector must be held in place on the'bulb. As the reflector is generally stronger than the lamp-bulb, it may also serve as a protector therefor in shipment and storage if properly secured.

A convenient means for- 'securingthe reflector in place on the bulb is a ring or nut 20, which screws down on the threaded stem 5 and bears on the top of the reflector. This ring may beof metal, rubber, or other mate- .rial which will not detract from the appear:

ance of the lamp. Of course the metallic thimble on stem 5 may overhang the reflector (see Fig. 6) or may have small fins 22 turned out over the top of the reflector. Other means may be provided for holding the reflector on the bulb, or theYeflector may be cemented at its lower edge to the bulb.

The coeflicient of expansion and contraction of glass is nearly equal under changes of temperature; but as the thin glass of a lamp-bulb expands and contracts much more quickly than the heavier glass of a prismatic reflector the presenceof an air-space prevents accident from unequal expansion.

In Figs. 5 and ,6 the general principles of the construction of'Fig. lare applied to produce a symmetrical lamp of peg-top form, and in Figs. 7 and 8 the same are applied to a pearshaped form. In each instance the bulb and reflector together form a symmetrical whole in the outline of a definite and common figure without projections, and to external appearance the bulb and reflector might be integral. In each case, however, there is an air-space between the upper part of the bulb and the prismatic reflector. The reflector covers this air-space and preferably covers the exhaustseal, which should be under the reflector.

The light-rays from the filament which have an upward tendency pass through the upper reduced portion of the bulb with little or no obstruction and encountering the prismatic reflector are directed back into and through the bulb and radiate at the lower surface of the bulb along with the. rays directly transmitted in. that direction. If the lower body of the bulbbe frosted orground, the li htwill be much softened and diflused.

As with other reflectors, the effective light in downward direction is nearly doubled, As the reflector is reduced toa minimum size, it is less in weight and in cost than Wouldbe a reflector having projections beyond the body of the bulb, As it is close to the bulb, it serves as a protector therefor, as has been ex plained.

Dust on the outer surface of the reflector does not interfere with its reflectivepower. As the reflector is generally above the bulb,

I it largely protects the illuminating-surface of -'When the bulb is suspended, the reflector may generally be supported thereon by its I the lamp from dust.

The prisms on the reflector do not entirely prevent the passage of light-rays. surface of thereflector presents an attractive v The outer I l i eter, and the reflector having its lower' edge resting on the bulb and its-outer surface form but subdued brilliancy, and the uncovered j body of the bulb gives a bright or a softened light,accordinglyas it is of clear or frosted glass.

The prismatic reflector should be of clear-glasa From the foregoing it will be perceived that both the reflector of the present invention and the lamp-bulb depart from usual construc tions for the purpose of adapting them for use 'with each other as a composite whole. Reflectors of glasshave generall'y beenmade heretofore with a collar orsome means of supl port at the top or with a flared part at. thelower extremity and have been adapted for use with many forms of. lamps; Lamp-bulbs havelbe'en made of many forms, but not, so far as I am aware, with areduced portion for thepurpose-of receiving a reflector which when added makes with the luminous portion of the bulba symmetrical whole. Such "abulb I do not herein claim, broadly, as it is coning'a continuation of the symmetrical outline 3O portion of the bulb.-

of the bulb, and its body covering the reduced 2. A compound" incandescent electrical lamp bulb and prismatic reflector of glass, the

V bulb having its lower portion of symmetrical form and its upper portion of reduceddiaming-a continuation of the outline of the bulb, the reflector covering the reduced portion of 1 the bulb.

3. Anincandescent lamp vbulb and reflector composed of glass, the bulbhaving itslower portion of symmetrical form and its upper portion of reduced diameter .relativelythere-.

to, and areflector having its lower edge resting on the enlarged portion of the bulb, its body covering the reduced portionof the bulb,

and its-outer surface substantially covered the're'flector to the bulb. A

7. The combination with an incandescent lamp bulb having its upper body portion of rereflecting-prisms.

with reflecting-prisms and forming a continu.

tion of the symmetrical body of the bulb.

4:, The combination with a lamp-bulb havingits upper body of reduced diameter and the exhaust-seal on this reduced. part'of its body, of an external reflector having its lower edge resting on the body of the bulb, and covering the exhaust-seal, said reflectorform-ing a symmetrical continuation of the enlarged portion of the lamp-bulb.

5. .The combination with an incandescent electrical lamp bulb having its upper body portion of reduced diameter and provided with a stem, of a prismatic-glass reflector having its lower edge resting on the enlarged portion of the bulb, said reflector mechanically secured to'said bulb by suitable means.

6. The combination with an incandescent electrical lamp-bulb having its lower body of symmetrical form and its upper portion of reduced diameter, of a reflector of prismatic 4 glass having its lower edge bearing onthe enlarged body of the bulb, and its outer surface forming a continuation of the symmetrical portion of the bulb, and means for'secu'ring duced diameter, 'of a glass reflector covering said reduced portion and having its lower edge means on the stem. for holding the reflector.

8. The combination with an incandescent- ;lamp bulb having. its lower portion symmetrical and externally frosted and its upper resting on the bulb, a stem on the bulb, and

portion v ofjreduced diameter, of a glass reflector having its lower edge resting on the bulb and its outer surface forming acontinuation' of the symmetrical outline of thebulb, said reflector covered externally byintegral In testimony whereof I aflix my signature in presence. of two witnesses.

., h .o'r s AMYGATT.

Witnes s esrf a C, A. Mc'O NN, e Gno. A, Con. 

